Hae Ji Kang

Complete Genome Sequence of Middle East Respiratory Syndrome Coronavirus KOR/KNIH/002_05_2015, Isolated in South Korea

ABSTRACT The full genome sequence of a Middle East respiratory syndrome coronavirus (MERS-CoV) was identified from cultured and isolated in Vero cells. The viral genome sequence has high similarity to 53 human MERS-CoVs, ranging from 99.5% to 99.8% at the nucleotide level.

Variations in Spike Glycoprotein Gene of MERS-CoV, South Korea, 2015

An outbreak of nosocomial infections with Middle East respiratory syndrome coronavirus occurred in South Korea in May 2015. Spike glycoprotein genes of virus strains from South Korea were closely related to those of strains from Riyadh, Saudi Arabia. However, virus strains from South Korea showed strain-specific variations.

Middle East Respiratory Syndrome in 3 Persons, South Korea, 2015

In May 2015, Middle East respiratory syndrome coronavirus infection was laboratory confirmed in South Korea. Patients were a man who had visited the Middle East, his wife, and a man who shared a hospital room with the index patient. Rapid laboratory confirmation will facilitate subsequent prevention and control for imported cases.

An increasing, potentially measles-susceptible population over time after vaccination in Korea

BACKGROUND In Korea, measles occurs mainly in infants <12months of age, who are unvaccinated. In addition, vaccine populations, including adolescents and young adults, can become infected though importation. Thus, the question arises whether the current level of herd immunity in Korea is now insufficient for protecting against measles infection. METHODS Age-specific measles seroprevalence was evaluated by performing enzyme immunoassays and plaque reduction-neutralization tests on 3050 subjects aged 0-50years (birth cohort 1964-2014) and 480 subjects aged 2-30years (birth cohort 1984-2012). RESULTS The overall seropositivity and measles antibody concentrations were 71.5% and 1366mIU/mL, respectively. Progressive decline in antibody levels and seropositivity were observed over time after vaccination in infants, adolescents, and young adults. The accumulation of potentially susceptible individuals in the population was confirmed by comparing data from 2010 and 2014 seroprevalence surveys. The statistical correlation between measles incidence and measles seronegativity was determined. CONCLUSIONS Waning levels of measles antibodies with increasing time post-vaccination suggests that measles susceptibility is potentially increasing in Korea. This trend may be related to limitations of vaccine-induced immunity in the absence of natural boosting by the wild virus, compared to naturally acquired immunity triggered by measles infection. This study provides an important view into the current measles herd immunity in Korea.

Resurgence of measles in a country of elimination: interim assessment and current control measures in the Republic of Korea in early 2014

Since the beginning of 2014, the Republic of Korea has experienced a resurgence of measles cases. Among the 220 cases confirmed as measles during epidemiological weeks 1-20 (December 29, 2013 to May 17, 2014), 10 imported cases were identified. The predominant genotype was B3, which reflects the circulating measles virus in adjacent countries. Even with the verification of measles elimination in March 2014 by the World Health Organization, recent importation has been related to international travel. Targeted control measures have been implemented in addition to proper isolation and patient care. A vigilant surveillance system and high levels of vaccine coverage should be maintained to sustain the measles elimination status.

Genetic characteristics of mumps viruses isolated in Korea from 2007 to 2012

Mumps is a vaccine‐preventable viral disease. Despite vaccine coverage of >95%, the incidence of mumps has increased in Korea since 2007. This study aimed to genetically characterize mumps virus (MuV) strains that circulated in Korea between 2007 and 2012 to determine the factors underlying mumps outbreaks. MuV was isolated from 175 clinical specimens between 2007 and 2012 in Korea. Upon analysis of the SH gene in Korean mumps virus isolates, three different genotypes were identified: I, H, and F. The MuV genotypes I and H co‐circulated in Korea, and eight isolates of Korean genotype F were found within the same time period in 2008. An analysis of HN amino‐acid sequence data showed that Korean isolates had no changes in their glycosylation sites. At putative neutralizing epitope sites, the Jeryl‐Lynn strain showed 4–5 different amino acid sequences from those observed in Korean isolates. Korean isolates of genotypes I and H shared distinctive point mutations on putative neutralizing epitope positions in each genotype. This report describes the genetic characteristics of MuV strains circulating in Korea and provides information on endemic mumps infections. This information may be important to help prevent mumps and control outbreaks of mumps in Korea. J. Med. Virol. 88:1479–1486, 2016.

How Can We Identify the Elimination of Infectious Diseases? Experience From an Active Measles Laboratory Surveillance System in the Republic of Korea.

Global efforts have markedly decreased the disease burden of vaccine-preventable diseases. Many countries have made considerable progress toward the elimination of measles. As elimination is approached, the very low incidence achieved by high vaccination coverage has underscored the need for a sensitive and timely surveillance system. In the Republic of Korea, an active laboratory surveillance system (ALSS) was implemented to supplement the existing passive surveillance system in 2006. The ALSS connects 5 major commercial laboratories and the national measles reference laboratory, where referred samples with positive or equivocal results are retested. Annually, from 2009 to 2013, 3714 suspected cases were detected through the ALSS, an expansion of 8- to 57-fold, compared with only the passive surveillance system. The ALSS, with its sensitivity and timeliness, is a reasonable strategy to supplement the existing measles surveillance system and to help identify the elimination of measles.

Occurrence of measles in a country with elimination status: Amplifying measles infection in hospitalized children due to imported virus

The Republic of Korea declared measles elimination in 2006. However, a measles outbreak occurred in 2013. This study aimed to identify the epidemiological characteristics of the sources of infection and the pattern of measles transmission in 2013 in South Korea. We utilized surveillance data, epidemiological data, immunization registry data, and genetic information. We describe the epidemiological characteristics of all measles case patients (sex, age distribution, vaccination status, sources of infection) as well as details of the outbreak (the pattern of transmission, duration, mean age of patients, and generation time). In 2013, a total of 107 measles cases were notified. Most patients were infants (43.0%) and unvaccinated individuals (60.7%). We identified 4 imported and 103 import-related cases. A total of 105 cases were related to four outbreaks that occurred in Gyeongnam, northern Gyeonggi, southern Gyeonggi, and Seoul. The predominant circulating genotype was B3 type, which was identified in the Gyeongnam, northern Gyeonggi, and southern Gyeonggi outbreaks. The B3 type had not been in circulation in South Korea in the previous 3 years; virologic evidence suggests that these outbreaks were import-related. Most measles cases in South Korea have been associated with imported measles virus. Although Korea has maintained a high level of herd immunity, clustering of susceptible people can cause such measles outbreaks.